Beware a harridan called Harmonia. She bites. And don’t kill her, either. She’ll pay you back with a horrible smell.

You might have noticed this bug flying around your garden or home recently. She prefers brightly lit spots in the fall sunshine, like the south side of houses or gutters painted in pale colours.

But if you live in a shady area, count yourself lucky. She’s unlikely to show up.

Harmonia, or to use her full name, Harmonia axyridis, is a certain kind of ladybug that has become a pest in Ontario. She’s commonly called the Asian lady beetle because that’s where she originated. Agricultural poohbahs brought her to North America to combat aphids on soybean crops, which she does very well but, unfortunately, since then she’s spread her wings and moved further afield

Now horrid Harmonia is getting into everyone’s hair. She’s a problem around the world, from South Africa to South America. Her infestations here, always in fall, tend to come and go. A few years ago, she created headaches for the Niagara wine industry. Earlier than that, I suddenly had great swarms of the bugs appear in my garden northwest of Toronto — so many, I couldn’t go outside without getting dive-bombed.

This fall, she’s back big time in some areas of the province, including mine, perhaps because last year’s hot dry summer gave her ideal conditions to breed.

How to recognize this pesky lady? Look closely at her colour. She isn’t the “good” ladybug, the one that kids love and that always gets trotted out in promotional stuff about beneficial insects. That ladybug is an eye-catching scarlet with black spots and doesn’t bite.

The Asian kind has the same spots, but her shell tends to be more brownish or coffee coloured (confusingly, she sometimes looks red as well) and —ouch — she definitely loves taking a chunk out of us mortals.

What harm does she cause in gardens? Truthfully, none, apart from being a nuisance to gardeners. But if you spot her hanging around your house or garage in big numbers, reach for the caulking gun.

Although this ladybug doesn’t lay her eggs indoors, she does seek out crevices in buildings and other protected places. And her impact can be awesome. I’ve turned over flowerpots stored in my basement and discovered literally hundreds of these bugs curled up there, sleeping off the winter. They found a way in, unnoticed, through a crack in the wall.

When spring comes, the little critters wake up, attracted to light. They start crawling around, emerging from baseboards, cracks in ceilings and walls, you name it. And if you squish them, they stink.

The smell that a dead Asian lady beetle emits (it’s actually her blood) is sometimes likened to “rancid peanut butter.” Whatever, it’s powerful and the taste is even worse. A couple of specimens found their way into my neighbour’s muffin batter. She gagged telling me the story.